(1) Field of the Invention
The present invention relates to a thermotherapy device effective in alleviating pains of various parts of the body, such as stiffness of the shoulders, backache, etc.
(2) Description of Related Art
Thermotherapy, which applies heat to the afflicted area, is one of the methods for alleviating pains of various parts of the body, such as stiffness of the shoulders. Such thermotherapy typically uses heat produced by an exothermic composition which comprises iron powder and a pro-oxidant and is accommodated in a bag. Such an exothermic composition, whose temperature is controlled to about 45° C., and is capable of maintaining the skin-temperature, for a predetermined period of time, within a range of about 38 to about 42° C. suitable for treating the afflicted area. Exothermic compositions are hence widely used in thermotherapy devices.
Conventional thermotherapy devices using such an exothermic composition, in general, comprise a single heat generation portion having an exothermic composition accommodated in a bag of a particular size. Such thermotherapy devices of the type having a single heat generation portion are known to work effectively for the purpose of intensively treating a single afflicted area. However, when a large thermotherapy device is attached to a rather long, broad part of the body for treating stiff shoulders, backache or the like, this may result in warming not only the muscles but also bones in deep region, inhibiting the intended treatment from being effectively applied. Moreover, when such a heat generation portion has excessively large area, it does not easily fit on onto curved parts of the body, such as the shoulders.
As such a thermotherapy device, for example, Patent Document 1 discloses a heat cell filled with a granular exothermic composition containing predetermined amounts of iron powder, activated carbon, metal salt, and water, wherein the ratio of the fill volume to the cell volume is 0.7 to 1.0, and the thickness of the heat cell is 0.15 to 1.0 cm. Further, Patent Document 2 teaches a thermotherapy device for the neck (thermal neck wrap) comprising a substantially triangular piece of flexible material, and a plurality of individual thermal elements (heat generation portions) embedded and fixed therein. The respective thermal elements of the thermal neck wrap correspond to the muscles in the user's upper back, lower neck, shoulders and the like to warm such parts of the body.
In each of the thermotherapy devices disclosed in the aforementioned Patent Documents 1 and 2, the heat generation portion or each heating element has limited dimensions such that it fits along a curved part, such as the neck. However, these heat generation portions, depending on where they are attached, fit poorly along body surfaces, and therefore do not necessarily achieve sufficient thermotherapy effects.    Patent Document 1: Japanese translation of PCT international application No. 11-508786 (WO97/01313)    Patent Document 2: Japanese translation of PCT international application No. 11-508785 (WO97/01312)